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Firefox crashes upon starting up

  • 8 replies
  • 2 have this problem
  • 34 views
  • Last reply by CuteMango

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Hello, I am currently unable to open Firefox on my Mac. When I try to open Firefox, the Mozilla Crash Reporter screen opens and states "Firefox had a problem and crashed. We'll try to restore your tabs and windows when it restarts". I then have the option to "Quit Firefox" or "Restart Firefox", and selecting "Restart Firefox" simply bring up another Mozilla Crash Reporter. If I restart firefox while holding the option key, the Firefox Safe Mode screen appears, giving me the option to "Refresh Firefox" or to "Start in Safe Mode". Selecting the safe mode option brings up another crash reporter screen, while refreshing firefox opens an empty box. I am then unable to quit firefox without having to force quit the application. I have tried deleting Firefox and reinstalling it, updating my Mac and restarting it and moving the Firefox and Profiles folders from my Library folder away (I would like to keep my data if possible), yet none of these steps have solved my problem.

Hello, I am currently unable to open Firefox on my Mac. When I try to open Firefox, the Mozilla Crash Reporter screen opens and states "Firefox had a problem and crashed. We'll try to restore your tabs and windows when it restarts". I then have the option to "Quit Firefox" or "Restart Firefox", and selecting "Restart Firefox" simply bring up another Mozilla Crash Reporter. If I restart firefox while holding the option key, the Firefox Safe Mode screen appears, giving me the option to "Refresh Firefox" or to "Start in Safe Mode". Selecting the safe mode option brings up another crash reporter screen, while refreshing firefox opens an empty box. I am then unable to quit firefox without having to force quit the application. I have tried deleting Firefox and reinstalling it, updating my Mac and restarting it and moving the Firefox and Profiles folders from my Library folder away (I would like to keep my data if possible), yet none of these steps have solved my problem.

Chosen solution

thanks, i was just recommending beta since the signature of your particular crash doesn't show up there anymore. some comments are referencing having switched to the macos dark mode or otherwise adjusting the system colours before the problem started - are you using dark mode as well?

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All Replies (8)

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What's your computer system and Firefox version?


If you can't get Firefox to open, you will have to do this the hard way.

https://support.mozilla.org/en-US/kb/mozillacrashreporter Open the file browser/explorer on your computer. Note: You may have to enable Show Hidden Folders / Files. Enter this in the address bar;

Windows: %APPDATA%\Mozilla\Firefox\Crash Reports\submitted Win 7/Vista: C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Crash Reports\submitted Win XP/2000: C:\Documents and Settings\<username>\Application Data\Mozilla\Firefox\Crash Reports\submitted

Mac OS: /Users/<username>/Library/Application Support/Firefox/Crash Reports/submitted Linux: /home/<username>/.mozilla/firefox/Crash Reports/submitted

The crash report is several pages of data. We need the report numbers to see the whole report.

Copy the most recent 5-7 File Names in the folder. Post the information in the reply box.

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My Mac is running macOS 10.14.3 and the firefox installer I have is 65.0.2. bp-3fc62f1a-63d7-45e7-afbc-85bba0190306 This is the only file in the submitted folder.

Out of curiosity, is there a way for me to completely uninstall firefox (without saving my data in the process) to fix this problem? (Since the usual process of deleting an application didn't seem to function.)

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hi, are you still able to reproduce this crash when using firefox 66 beta? www.mozilla.org/beta

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Firefox comes in two or more folders on all computers. They are;

Maintenance: (Programs Folder) <Windows Only> Firefox itself: (Programs Folder) And two folders in the profile of each user on the computer for each Firefox profile for that user.

If you remove the Firefox folder, the user profiles would not be affected.

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After replacing firefox 65 by firefox 66 beta, the crash sequence is gone and firefox opens normally, although tabs aren't displayed in the beta, and trying to close firefox brings up a blank box, which I suppose displays the standard warning message when closing tabs. Does this mean that there is something wrong with firefox 65 and that I would have to use a different browser until firefox 66 is released?

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'Beta' versions are prone to problems. Those problems get discovered by the testers and get reported to be acted on.

https://www.mozilla.org/en-US/firefox/channel/desktop/

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Chosen Solution

thanks, i was just recommending beta since the signature of your particular crash doesn't show up there anymore. some comments are referencing having switched to the macos dark mode or otherwise adjusting the system colours before the problem started - are you using dark mode as well?

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Yes, I had dark mode on previously. I switched it off though once it started crashing, but it didn't help much. Thank you very much for your help! :)